PIP(1) General Commands Manual PIP(1) NAME PIP - package for parsing input parameters from Fortran or C USER DESCRIPTION PIP is a package of functions for entering parameters into programs. A program using PIP will accept input in two different ways. Options and their values can be entered as command line arguments, or on separate lines with one option name per line followed by its value. The multi-line entry can be made via standard input, on lines following the command line invoking the program; in addition, the program may also allow entries in this format to be read from a separate parameter file. These different methods may even be used together, with some options taken from the command line and some from line entries. Options are generally given both a short and long name, with the short name designed for convenience when used at the command line, and the long name being more descriptive for use in command files. However, either form may be used in either place. The names are case-sensitive. Options can be abbreviated to their shortest unique form, sometimes one or two letters. When entered at the command line, options must be preceded by one or two dashes (- or --). The option must be followed by a space then a value if appropriate. If the value contains embedded blanks it must be enclosed in quotes. Options cannot be concatenated the way single letter options in Unix programs often can be. Multiple-line entry is invoked by entering the argument -StandardInput on the command line, or, if the program allows, by entering the option to read a parameter file, followed by the name of the file. The program will read lines of input until the tag EndInput is read or until the end of the file is reached. It will then resume processing command line arguments, if any. The format of the line entry is an option name followed by any number of spaces or tabs and an optional equals sign, followed by the value of the option. If the value consists of multiple numbers, they can be separated by spaces, tabs or commas. If a value consists of a text string, it may contain embedded blanks. Blank lines and lines starting with # are ignored. A comment starting with # can also be placed on a line after an option and its value. Programs may allow Fortran-style default input, in which a comma without a number indicates that the default value for the number should be taken, and a / indicates that all remaining numbers have their default values. For example, 23,,15 takes the default for the second value and ,42,17 takes the default for the first; 1,1024/ takes the default for all values after the first two and / takes the default for all values. Defaults can be used only when a fixed number of values are expected. Boolean options are ones that turn a particular feature on or off. When entered as command lines arguments, they must not be followed by a value; in other words, the presence of the entry sets the option to true or on. However, when a boolean option is entered in a separate line in a command file, it may be followed by 0, F, f, FALSE, false, OFF, off, 1, T, t, TRUE, true, ON, or on. Options can be entered more than once. In most cases a later value will supercede a previous entry, but in some cases the multiple entries will accumulate. This is useful if multiple input file names are needed, or if more numbers need to be entered than will fit on a line. In rare cases, each entry of an option is associated with (linked to) the next entry of another option; this is the only situation where the order of entering different options matters. PIP provides a standard help output which the program should make available with an option such as -help or -usage. Invoking a program with no arguments may also cause this to be printed, unless the program still supports old-style interactive input as the default when there are no arguments. The help output will list the two forms for each option, indicate what kind of value is expected, and provide a one-line description of the option. In addition, it will indicate if multiple entries of an option will accumulate. The man page and usage output will also show the current shortest unique short name for each option in parentheses. These allowed abbreviations can change when new options are added, but should never become longer than three letters. Thus, when writing a script that runs a program with short option names, always use at least 3 letters for each option. For example, suppose you wanted a shell script to run newstack and reduce a file by the number in its first argument and convert to bytes, with input and output files in the second and third arguments. To use the command line format, you could write newstack -mod 0 -flo 2 -shr $1 "$2" "$3" where the $2 and $3 are quoted because they might contain spaces, and every option is specified with 3 letters. Sequential input would be written as newstack -StandardInput << ENDHERE InputFile $2 OutputFile $3 ModeToOutput 0 FloatDensities 2 ShrinkByFactor $1 ENDHERE where the "ENDHERE" is an arbitrary delimiter. Note that the input can be indented for clarity. PROGRAMMING DESCRIPTION The simplest way to use PIP is first to set up its state with optional calls to PipExitOnError and PipAllowCommaDefaults, then pass it the list of options and have it parse input with PipParseInput, then get option values with a series of PipGet... calls, then finish with PipDone. PIP can also read the list of options from a separate file, referred to as an autodoc file. In this case, instead of calling PipParseInput, one calls PipReadOptionFile to read the options from the file, then PipParseEntries to parse the input. There is also a convenience function, PipReadOrParseOptions, that will first try to read options from an autodoc file, then fall back to a list of options supplied by the calling program. For use from C, the header file parse_params.h is in the IMOD/include directory. The PIP package and Fortran-callable wrappers are in the libcfshr library. The Fortran versions of PipParseInput and PipReadOptionFile are in the libhvem library, which requires libcfshr. Fortran-callable wrappers to the C functions have been given the same name as the C functions, although internally they are all lower case with an underscore appended, or all uppercase in Windows. The function calls from Fortran are case-insensitive but they are shown with mixed case here for clarity. PIP can also be used from Python by importing the pip module in the IMOD/pylib directory. Up to IMOD 3.11 this was a compiled extension module using the C code, but this is now written in Python to avoid compatibility problems. The calling conventions are described in a separate section below. Option Specifications Supplied by the Calling Program Each legal option should be specified with a string having up to 4 components: shortName:longName:type:helpString The short name is intended to be used predominantly on the command line, while the long name would be more suitable in parameter files. However, PIP makes only one distinction between the short and long names - if a short name consists of a single letter, there can be other short names starting with that letter. Either name can be abbreviated, either name can be preceded by either one or two dashes, and either name can be omitted. Any of these 4 components can be omitted as long as there is either a short or a long name. The string must have 3 colons. Option Types B Boolean - the only type that does not require a value I Integer IP Pair of integers IT Three integers IA Integer array F Floating point FP Pair of floating point numbers FT Three floating point numbers FA Floating point array CH Character string FN File name LI List (comma-separated list of ranges) PF Parameter file If an option specification ends in M or L, this indicates that multiple entries of the option will accumulate rather than supercede each other. This allows multiple filenames of a particular type to be entered, or multiple lines of input for long lists of numbers. The L ending indicates that each entry of the option is associated with, or linked to, the next occurrence of some other option. It must be specified in order to use the PipLinkedIndex function. PIP uses these types primarily to provide information in the help output and does not enforce the implications of these types, except as follows: an option that does not take an argument must be coded as B; a parameter file option must be coded as PF. Option Specifications in an Autodoc File The autodoc file is designed to provide a single source of information about program options for the program itself, the man page, and graphical user interfaces that run the program. The file consists of global metadata at the start, then a series of sections starting with a token inside brackets. Each section can then contain keyword-value pairs. The general form of a token entry is: [token delimiter value] and the general form of a keyword-value pair is: keyword delimiter value Tokens, keywords, and token values must not contain embedded spaces, although keyword values may. There must be no space between the opening [ and a token or between its value and the ending ]. There can be spaces or tabs before and after the delimiter; these will not be considered part of the token or value strings. PIP will ignore white space before keywords or tokens, but other parsers of autodoc files may not accept this. The default delimiter is an equals sign (=). It can be changed once, in the metadata, before any tokens have been encountered, with a statement such as: KeyValueDelimiter = == PIP will examine keyword-value pairs only after a Field token, which signifies the start of an option, or after a SectionHeader token, which can be used to introduce some header text into the usage or manpage outputs. The following keywords are understood by PIP in a Field section, while others are ignored: short Short option name long Long option name type Type of option; see table above format String shown after the option in usage or manpage output default Default value returned when no option is entered usage Help string for usage output tooltip Help string for tooltip manpage Help string for manual page If one of these keywords has no value after it, PIP will ignore the entry. Short and long option names should not contain spaces. If a Field has a value, it becomes the default long option name, in which case long can be omitted. Alternatively, a long entry can be used to override the value of the field, and a blank long entry can be used to eliminate the default long option name provided by a Field value. If a format entry is destined for a .man-type manpage, it will be italicized by default by wrapping it in \fI and \fR. It can contain these kind of font specifiers, and the default wrapping will be omitted if it starts with one of the specifiers. Thus, enclose the entry in \fB and \fR or start it with \fR to have it be in bold or regular font. The help strings are allowed to contain spaces, and to continue on multiple lines. A continuation line should not have # or [ as its first non-white space character, nor should it contain the key-value delimiter. Lines are added to a help string until a line with the delimiter is encountered. If you want to use = in help strings, change the delimiter to == as shown above, or enclose the entire (possibly multiline) string in quotes. The quote can be a single quote, double quote, or backtick character. PIP will look for a matching quote only at the end of a line, but other autodoc parsers may be confused by a matching quote embedded in the line, so it is best to use a quote that is not used literally in the string. Use ^ at the beginning of a continuation line to start a new line before outputting the text on the line. Spaces after the ^ will be retained, so that lines can be indented in a man page. Lines containing only white space, and lines with # as the first non-white space, are ignored. If a default value is supplied with the default entry, help strings can contain %{default}, which will be substituted with the default value. Do not change delimiters from = when using default values, because then these entries will not be recognized by the script that creates a fallback list of default settings, which is used when an autodoc cannot be found. Defaults cannot be set for boolean options. In a SectionHeader section, keywords besides usage and manpage are ignored. Help strings will be output without indentation; for a man page that is input to nroff, start the string with .SS or .SH to avoid the regular indentation of option text. Other meaningful metadata entries are NoHelpAbbrevations to avoid showing unique abbreviations in help output, NoAbbreviations to turn on the flag for no abbreviations internally and allow otherwise ambiguous options, and DoubleDashOptions to show options with two dashes in help output. Errors and Return Values All functions return a negative number if an error occurs. Functions in which an option is specified typically return -1 if the option is not a legal one, or -2 if the option is abbreviated ambiguously. An error string is available after an error by calling PipGetError. Alternatively, the program can call PipExitOnError at any point, and PIP will print the error string itself and exit with an error status. Functions for Initialization int PipExitOnError(int useStdErr, const char *prefix); integer*4 function PipExitOnError(useStdErr, prefix) integer*4 useStdErr character*N prefix Use this function to enable PIP to exit with a message upon any error in program function or user input. The string prefix will be placed in front of the error message that PIP ordinarily generates upon error, and the message will be printed to standard output or standard error depending on whether useStdErr is 0 or 1. PIP will exit with an error status. If prefix is an empty string, then this feature is disabled. void PipAllowCommaDefaults(int val); subroutine PipAllowCommaDefaults(val) integer*4 val If Ival is non-zero, then Fortran-style default input will be allowed whenever a fixed number of values are being returned. Specifically, if commas are used to separate entries and there is no entry between a pair of commas, then the returned value will be unmodified from the default value supplied in the call. A / character will terminate input and leave all remaining expected elements at their default values. void PipSetSpecialFlags(int noCase, int doneEnds, int takeStdin, int nonOptLines, int noAbbrevs) subroutine PipSetSpecialFlags(noCase, doneEnds, takeStdin, nonOptLines, noAbbrevs) integer*4 noCase, doneEnds, takeStdin, nonOptLines, noAbbrevs This call can be used to set flags that modify the behavior as follows: noCase non-zero allows case-insensitive options doneEnds non-zero allows DONE to be used in place of EndInput takeStdin 1 or 2 runs a program with no arguments as if -StandardInput were entered; 1 works from Fortran and 2 is needed from C. nonOptLines greater than zero allows the first few lines of input to be taken as non-option arguments, up to a number of lines given by the value. noAbbrevs non-zero means that options must be entered in full The first four behaviors were required to convert Tilt to PIP input without retaining the old input code, but none of this should be needed elsewhere. int PipSetLinkedOption(const char *option); integer*4 function PipSetLinkedOption(option) character*N option This function will set a specific option as the linked option, so that the current count (index of next occurrence) of that option will be recorded for each entry of other options. int PipParseInput(int argc, char *argv[], const char *options[], int numOptions, int *numOptArgs, int *numNonOptArgs); integer*4 function PipParseInput(options, numOptions, separator, numOptArg, numNonOptArg) character*N options(N) integer*4 numOptions character separator integer*4 numOptArg, numNonOptArg [Returned arguments] This is a high-level function that will initialize PIP (PipInitialize) for the number of options given in numOptions, take the list of all available options specified in options and add them one at a time with PipAddOption, parse command line arguments and other input with PipNextArg, and return the number of option arguments in numOptArg and the number of non-option arguments in numNonOptArg. At the end, it calls PipPrintEntries, which will print program entries if enabled (see below). The C version receives the command line arguments directly while the Fortran version fetches them with getarg. There are two alternatives for Fortran usage. Each option specification can be placed in a separate element of the options array. In this case, options should be dimensioned to the number of options, separator should be a space character, and the length of the character elements of the array should at least as big as the longest option description. Alternatively, all of the options can be placed in one character string, separated by the character given in separator. In this case, set the dimension of options to 1 and make its length be big enough for the entire string. int PipReadOptionFile(const char *progName, int helpLevel, int localDir) integer*4 function PipReadOptionFile(progName, helpLevel, localDir) character*N progName integer*4 helpLevel, localDir This function will read options from an autodoc file, progName.adoc. If localDir is 0, this file will be sought first in the directory pointed to by the environment variable AUTODOC_DIR, if it is defined; then in the directory $IMOD_DIR/autodoc; then in the current directory. If localDir is 1 or 2, etc., the file will be sought in ../autodoc or ../../autodoc, etc., then in the current directory. This allows PIP to generate a man page entry from the autodoc file in the current source tree rather than in the installed version of IMOD. The helpLevel argument determines which help string is used when multiple strings are available. If helpLevel is 1, then the usage string will be stored if available, or the tooltip string if there is no usage string, or the manpage string if neither tooltip nor usage is available. If helpLevel is 2, then the tooltip string will be stored if available, or the usage string if there is no tooltip string, or the manpage string if neither tooltip nor usage is available. If helpLevel is 3, then the manpage string will be stored if available, or the tooltip string if there is no manpage string, or the usage string if neither tooltip nor manpage is available. int PipParseEntries(int argc, char *argv[], int *numOptArgs, int *numNonOptArgs); integer*4 function PipParseEntries(numOptArg, numNonOptArg) integer*4 numOptArg, numNonOptArg [Returned arguments] This high-level function is used after options have been read from an autodoc file with PipReadOptionFile. It parses command line arguments and other input with PipNextArg, and return the number of option arguments in numOptArg and the number of non-option arguments in numNonOptArg. The C version receives the command line arguments directly while the Fortran version fetches them with getarg. subroutine PipReadOrParseOptions(options, numOptions, progName, exitString, interactive, minArgs, numInFiles, numOutFiles, numOptArg, numNonOptArg) character*N options character*N progName character*N exitString logical interactive integer*4 minArgs, numInFiles, numOutFiles integer*4 numOptArg, numNonOptArg [Returned arguments] This Fortran subroutine performs a sequence of initialization tasks. It first attempts to read options for the program progName from an autodoc file using PipReadOptionFile then PipParseEntries. If this fails, it falls back to calling PipParseInput to define numOptions options from the single string options, with the separator @ between options. It allows comma defaults with PipAllowCommaDefaults, and calls both PipExitOnError and setExitPrefix with the prefix string in exitString. If interactive is .true., the routine returns if there are no input arguments. Otherwise, it checks for whether to print a usage output. If the number of arguments is less than minArgs or -help is entered as an argument, then it calls PipPrintHelp with numInFiles and numOutFiles as arguments for the number of input and output files, then exits. The option help must therefore be defined. void PipReadOrParseOptions(int argc, char *argv[], const char *options[], int numOptions, const char *progName, int minArgs, int numInFiles, int numOutFiles, int *numOptArgs, int *numNonOptArgs, void (headerFunc)(const char *)); This C function performs a similar sequence of initialization tasks. It first attempts to read options for the program progName from an autodoc file using PipReadOptionFile then PipParseEntries. If this fails, and if numOptions options are provided in an array of strings, options, it falls back to calling PipParseInput. It calls PipExitOnError with "ERROR: progName - " as the error string, defining standard out as the destination for error output. If the number of arguments is less than minArgs, it first calls the function supplied in headerFunc if it is non-NULL, then calls PipPrintHelp with numInFiles and numOutFiles as arguments for the number of input and output files, then exits. int PipInitialize(int numOpts); integer*4 function PipInitialize(int numOpts) integer*4 numOpts This function will initialize PIP and allocate memory for the number of options given in numOpts. int PipAddOption(const char *optionString); integer*4 function PipAddOption(optionString) character*N optionString This function is used to add one option at a time to PIP's table of options. int PipNextArg(const char *argString); integer*4 function PipNextArg(argString) character*N argString This function is used to send each argument in turn to PIP. An option will be checked against the list of legal options; a value for an option will be associated with the option in PIP's table; and a non-option argument will be stored in PIP's list of those. The function returns 1 if an argument is an option that requires a value. void PipNumberOfArgs(int *numOptArgs, int *numNonOptArgs); subroutine PipNumberOfArgs(numOptArgs, numNonOptArgs); integer*4 numOptArg, numNonOptArg [Returned arguments] After arguments have been parsed, this function returns the number of option arguments in numOptArg and the number of non-option arguments in numNonOptArgs. Functions for Getting Values int PipNumberOfEntries(const char *option, int *numEntries); integer*4 function PipNumberOfEntries(option, numEntries); character*N option integer*4 numEntries [Returned argument] This function returns the number of accumulated entries for the given option in the argument numEntries. After calling this function, simply call a function to get the value of the option that number of times to retrieve all of the entered values. int PipLinkedIndex(const char *option, int *Iindex); integer*4 function PipLinkedIndex(option, index); character*N option integer*4 index [Returned argument] This function returns into the argument index the index of the next entry of a linked option, for the next entry of the given option to be retrieved. It returns the index of a specific linked option if one was identified with PipSetLinkedOption and if entries were made with that option; otherwise it returns the index of the next nonoption argument. int PipGetNonOptionArg(int argNo, char **arg); integer*4 function PipGetNonOptionArg(argNo, arg) integer*4 argNo character*N arg [Returned argument] This function returns the non-option argument specified by argNo (numbered from 0 in C and Python, from 1 in Fortran) in as a string in the argument arg. Note that non-option arguments can also be retrieved by calling PipGetString repeatedly with the option as NonOptionArgument or any abbreviation thereof. When called from C and a string is returned, the string is allocated with malloc() and should be freed with free(). int PipGetString(const char *option, char **string); integer*4 function PipGetString(option, string) character*N option character*N string [Returned argument] This function returns the value of the given option as a string in the argument string. The return value is 1 or 2 if the user did not enter this option (2 if a default value from autodoc was returned). When called from C and a string is returned, the string is allocated with malloc() and should be freed with free(). int PipGetInteger(const char *option, int *val); integer*4 function PipGetInteger(option, val) character*N option integer*4 val [Returned argument] int PipGetFloat(const char *option, float *val); integer*4 function PipGetFloat(option, val) character*N option real*4 val [Returned argument] These functions returns a single integer or floating point value for the given option in the argument val. The return value is 1 or 2 if the user did not enter this option (2 if a default value from autodoc was returned). int PipGetTwoIntegers(const char *option, int *val1, int *val2); integer*4 function PipGetInteger(option, val1, val2) character*N option integer*4 val1, val2 [Returned arguments] int PipGetTwoFloats(const char *option, float *val1, float *val2); integer*4 function PipGetTwoFloats(option, val1, val2) character*N option real*4 val1, val2 [Returned arguments] These functions returns two integers or two floats for the given option in the arguments val1 and val2. The return value is 1 or 2 if the user did not enter this option (2 if a default value from autodoc was returned). int PipGetThreeIntegers(const char *option, int *val1, int*val2, int*val3,); integer*4 function PipGetInteger(option, val1, val2, val3) character*N option integer*4 val1, val2, val3 [Returned arguments] int PipGetThreeFloats(const char *option, float *val1, float*val2, float*val3); integer*4 function PipGetThreeFloats(option, val1, val2, val3) character*N option real*4 val1, val2, val3 [Returned arguments] These functions returns three integers or three floats for the given option in the arguments val1, val2, and val2. The return value is 1 or 2 if the user did not enter this option (2 if a default value from autodoc was returned). int PipGetBoolean(const char *option, int *val); integer*4 function PipGetBoolean(option, val) character*N option integer*4 val [Returned argument] This function returns a value of 0 or 1 for the given boolean option in the argument val. The return value is 1 if the user did not enter this option. integer*4 function PipGetLogical(option, val) character*N option logical val [Returned argument] This function returns a value of .true. or .false. for the given boolean option in the argument val. The return value is 1 if the user did not enter this option. int PipGetIntegerArray(const char *option, int *array, int *numToGet, int arraySize); integer*4 function PipGetIntegerArray(option, array, numToGet, arraySize) character*N option integer*4 array(N) [Returned argument] integer*4 numToGet [Returned argument if initially 0] integer*4 arraySize int PipGetFloatArray(const char *option, float *array, int *numToGet, int arraySize); integer*4 function PipGetFloatArray(option, array, numToGet, arraySize) character*N option real*4 array(N) [Returned argument] integer*4 numToGet [Returned argument if initially 0] integer*4 arraySize These functions return an array of integers or floating point values for the given option. The argument numToGet should be set to the number of values to be retrieved, or to 0 or -1 if a variable number of entries is allowed. A value of 0 will result in an error if there are more values on the line than fit in the array; a value less than 0 will just get as many values as fit in the array and ignore extra ones. In either case, the functions will return the number of values in numToGet. The size of array should be specified in arraySize. The return value is 1 or 2 if the user did not enter the given option (2 if a default value from autodoc was returned). int PipGetInOutFile(const char *option, int nonOptArgNo, char **filename) integer*4 function PipGetInOutFile(option, nonOptArgNo, prompt, filename) character*N option, prompt integer*4 nonOptArgNo character*N filename [Returned argument] This function gets a filename specified by option; if that option was not entered, it gets the non-option argument in the nonOptArgNo position (numbered from 0 in C and Python, from 1 in Fortran). If that argument does not exist either, it returns with an error. Alternatively for Fortran, if interactive input is being used, it prompts for the filename interactively with the string in prompt. If there is no interactive input, supply an empty string for prompt. To prevent the function from looking for a non-option argument, call it with nonOptArgNo bigger than the value of numNonOptArg. Functions for Help, Entry Printing, Cleanup, and Errors int PipSetManpageOutput(int type); subroutine PipSetManpageOutput(type) integer*4 type This function stores type in the static variable outputManpage to control the type of help output. If the value is left at 0, a standard usage output is produced. A value of 1 produces output for a man page to be interpreted by nroff (a .man file), while -1 produces output for a preformatted man page (a .1 file). A value of -2 produces the complete Fortran code for a fallback option string, while 2 or 3 produce output for C or Python code defining an array of option strings, all suitable for passing to PipReadOrParseOptions. int PipSetUsageString(const char *usage); integer*4 function PipSetUsageString(usage) character*N usage This function allows you set a custom usage string to replace the default output entirely. PIP will print a newline after this string so it need not be included. A multiline string can be supplied with embedded newlines. int PipPrintHelp(const char *progName, int useStdErr, int inputFiles, int outputFiles); integer*4 function PipPrintHelp(progName, useStdErr, inputFiles, outputFiles) character*N progName integer*4 useStdErr, inputFiles, outputFiles This function produces a complete, formatted listing of options and their help strings, depending on the value of outputManpage as described just above. The program name should be supplied in progName. The listing is sent to standard output or standard error depending on whether useStdErr is 0 or 1. The usage summary includes input_file or input_files... if inputFiles is 1 or 2, respectively; and output_file or output_files... if outputFiles is 1 or 2 respectively. void PipEnableEntryOutput(int enable); subroutine PipEnableEntryOutput(enable) integer*4 enable This call controls whether PipPrintEntries will print the entries to the program. If enable is 1, printing is enabled; if it is 0 printing is disabled, and if it is -1 then printing is controlled by the value of the environment variable PIP_PRINT_ENTRIES. void PipPrintEntries(void); subroutine PipPrintEntries() This call causes the module to print a summary of all options entered to the program, if enabled either by a call to PipEnableEntryOutput or by the environment variable PIP_PRINT_ENTRIES. The header line will include the program name if PipReadOptionFile was used for startup. void PipDone(void); subroutine PipDone() This call frees all allocated memory and reinitializes all variables so that another complete round of processing could occur. int PipGetError(char **errString); integer*4 function PipGetError(errString) character*N errString [Returned argument] Use this function to get the error string generated by PIP from the last error. When called from C and a string is returned, the string is allocated with malloc() and can be freed with free(). int PipMemoryError(void *ptr, const char *routine); Tests ptr and returns 0 if it is non-NULL; otherwise it makes up an error string including the name given in routine and calls PipSetError, then returns -1. int PipSetError(const char *errString); Sets the error string and, if PIP has been set to exit on error, prints an error message and exits. void exitError(const char *format, ...); subroutine exitError(errString) character*N errString void setExitPrefix(const char *prefix); subroutine setExitPrefix(prefix) character*N prefix subroutine memoryError(ierr, errString) integer*4 ierr character*N errString exitError exits after printing an error string after a prefix, which is set by calling setExitPrefix. The Fortran version takes the error string while the C version takes variable arguments like printf. A space will be printed between the prefix and error string, and a newline printed after the error, so it is not necessary to include a newline in the string. The prefix is also set automatically by calling PipReadOrParseOptions or PipExitOnError; in the latter case the destination for error output can be specified, whereas using setExitPrefix will cause output to go to standard out. These two functions can be used by programs that do not call anything else in PIP; however, exitError will work only if the exit prefix has been set to a non-empty string with either setExitPrefix or PipExitOnError. The Fortran routine memoryError tests whether ierr is nonzero and, if so, calls exitError with errString appended to "FAILURE TO ALLOCATE ". Calling from Python The Python versions of the functions handle returned values differently: the values that would be returned in the function arguments in C or Fortran are returned in a single object as the return value of the function. For functions with multiple values, this will be a tuple. When an error occurs, this will be None. The value corresponding to the return value from a C function is obtained by calling the function PipGetErrNo. Functions that in C do not return any values except for the error code also set the error code for retrieval by PipGetErrNo and return 0 for success or None for an error. If you do not set PIP to exit on error, then you need to process return values in two steps, as in: retval = PipGetThreeIntegers('option', ix, iy, iz) if retval == None: process the error (ix, iy, iz) = retval This is not needed if PIP exits on error. In that case, if you need to determine whether an option was entered, use: (ix, iy, iz) = PipGetThreeIntegers('option', ix, iy, iz) optionEntered = 1 - PipGetErrNo() Here are the conventions for all of available function calls: Functions for Initialization: status = PipExitOnError(useStdErr, prefix) PipSetLinkedOption(option) (numOptArgs, numNonOptArgs) = PipParseInput(sys.argv, options) PipReadOptionFile(progName) In the call to the C function, the helpLevel argument is set at 1 and the localDir argument is set at 0. (numOptArgs, numNonOptArgs) = PipParseEntries(sys.argv) (numOptArgs, numNonOptArgs) = PipReadOrParseOptions(sys.argv, options, progName, minArgs, numInFiles, numOutFiles) These are similar to the C functions described above. options should be a list of strings as in the call to the C function. If -help is defined as an option and the user adds this option, then PipReadOrParseOptions will print the usage and exit as in Fortran. status = PipInitialize(numOpts) (numOptArgs, numNonOptArgs) = PipNumberOfArgs() Functions for Getting Values: When an option is not entered, the function returns the supplied argument value(s), or a default value if one is defined in an autodoc. numEntries = PipNumberOfEntries(option) index = PipLinkedIndex(option) string = PipGetNonOptionArg(nonOptArgNo) string = PipGetString(option, string) iVal = PipGetInteger(option, iVal) fVal = PipGetFloat(option, fVal) (iVal1, iVal2) = PipGetTwoIntegers(option, iVal1, iVal2) (fVal1, fVal2) = PipGetTwoFloats(option, fVal1, fVal2) (iVal1, iVal2, iVal3) = PipGetThreeIntegers(option, iVal1, iVal2, iVal3) (fVal1, fVal2, fVal3) = PipGetThreeFloats(option, fVal1, fVal2, fVal3) iVal = PipGetBoolean(option,iVal) iArray = PipGetIntegerArray(option, numToGet) fArray = PipGetFloatArray(option, numToGet) These two functions return the arrays as lists of values. As for the C functions, numToGet specifies the number to return, or 0 to return all available values. filename = PipGetInOutFile(option, nonOptArgNo) Functions for Help, Cleanup, and Errors: status = PipPrintHelp(progName, useStdErr, inputFiles, outputFiles) PipEnableEntryOutput(enable) PipPrintEntries() PipDone() errStr = PipGetError() errNo = PipGetErrNo() status = PipSetError(errString) exitError(string) setExitPrefix(prefix) AUTHOR David Mastronarde (mast at colorado dot edu) IMOD 4.11.0 PIP(1)