Process

Run a shell command and capture its standard output as a string.

Usage

Call lf_capture_system() with a command and an initial buffer size. Pass 0 to use the default size. The buffer grows as output is read.

char *cap = lf_capture_system("printf 'hello\\n'", 0);
if (cap != NULL) {
    printf("%s", cap);
    free(cap);
}

The returned string is yours to free. The command runs through /bin/sh without sanitizing; do not pass untrusted input.

Functions

lf_capture_system

Runs a command through popen() and returns its standard output as a heap allocated, NUL-terminated string. buf_sz is the initial buffer size; 0 uses LF_CAPTURE_SYSTEM_BUFSIZE (1024).

Returns NULL if cmd is NULL, buf_sz is 1, or starting the command, allocating memory, reading, or waiting for the child fails. A nonzero command exit status still returns the captured output. Standard error is not captured unless the command redirects it.

char *lf_capture_system(const char *cmd, size_t buf_sz);