XtFindFile man page
XtFindFile — search for a file using substitutions in the path list
String XtFindFile(String path, Substitution substitutions, Cardinal num_substitutions, XtFilePredicate predicate);
Specifies a path of file names, including substitution characters.
Specifies a list of substitutions to make into a path.
Specifies the number of substitutions passed in.
Specifies a procedure to call to judge a potential file name, or NULL.
The path parameter specifies a string that consists of a series of potential file names delimited by colons. Within each name, the percent character specifies a string substitution selected by the following character. The character sequence “%:” specifies an embedded colon that is not a delimiter; the sequence is replaced by a single colon. The character sequence “%%” specifies a percent character that does not introduce a substitution; the sequence is replaced by a single percent character. If a percent character is followed by any other character, XtFindFile looks through the specified substitutions for that character in the match field and if found replaces the percent and match characters with the string in the corresponding substitution field. A substitution field entry of NULL is equivalent to a pointer to an empty string. If the operating system does not interpret multiple embedded name separators in the path (i.e., “/” in POSIX) the same way as a single separator, XtFindFile will collapse multiple separators into a single one after performing all string substitutions. Except for collapsing embedded separators, the contents of the string substitutions are not interpreted by XtFindFile and may therefore contain any operating-system-dependent characters, including additional name separators. Each resulting string is passed to the predicate procedure until a string is found for which the procedure returns True; this string is the return value for XtFindFile. If no string yields a True return from the predicate, XtFindFile returns NULL.
If the predicate parameter is NULL, an internal procedure that checks if the file exists, is readable, and is not a directory will be used.
It is the responsibility of the caller to free the returned string using XtFree when it is no longer needed.
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