--- name: "pmfstring" section: "3" platform: "linux" package: "pcp" version: "7.2.2-2" release: "Arch Linux 2026-11-01" platforms: ["linux"] url: "https://new.carta.tech/pmfstring" --- # pmfstring(3) safe string scanning ## NAME **pmfstring** - safe string scanning ## C SYNOPSIS **#include \** **ssize\_t pmfstring(FILE \****f***, char \*\****str***);** **cc ... -lpcp** ## DESCRIPTION **pmfstring** is a safe string scanning routine with semantics similar to [**fscanf**(3)](/fscanf/3.md) with the **%s** format specifier. It scans the input stream from *f* skipping initial whitespace characters, then accumulating all the subsequent non-whitespace characters. The main difference is that **pmfstring** allocates the result buffer *str* using the [**malloc**(3)](/malloc/3.md) family and ensures that *str* is (a) large enough and (b) null-byte terminated. Additionally **pmfstring** does not consider \\n to be a whitespace character in the initial scan (before filling *str*) and so will not scan past the end of the current line, which is different to [**fscanf**(3)](/fscanf/3.md) and better aligned with the PCP use cases. The caller is responsible for maintaining a reference to *str* or calling [**free**(3)](/free/3.md) to release the associated storage. On success, **pmfstring** returns the length of *str* (the same length as [**strlen**(3)](/strlen/3.md) would return) that is guaranteed to be not less than 1. Failure is indicated by one of the following, and *str* is not assigned a value: - • 0 to indicate no non-whitespace characters were found before the end of the current line from the stream *f* - • \-1 ( aka **EOF**) to indicate end of file on the stream *f* - • \-2 to indicate some more serious failure, probably in the [**malloc**(3)](/malloc/3.md) routines; refer to *errno* for more information ## COMPATIBILITY **pmfstring** has similar semantics to the **%ms** format specifier in some versions of [**fscanf**(3)](/fscanf/3.md) and the C99 **fscanf\_s**(3) routine - unfortunately neither of these is portable. ## SEE ALSO [**free**(3)](/free/3.md), [**fscanf**(3)](/fscanf/3.md), [**malloc**(3)](/malloc/3.md) and [**strlen**(3)](/strlen/3.md).