[GENERAL] Exception Handling in C-Language Functions?

[Felix E. Klee]

I have the created a C-Language function (code is below).  Now, I
wonder: How do I handle exceptions, for example if malloc cannot assign
the necessary memory?  Do "palloc" and "pfree" handle such a case
cleanly?  Should I simply use an "assert"?

#include "postgres.h"
#include <string.h>
#include <stdlib.h>
#include "fmgr.h"
#include "libinn.h"

PG_FUNCTION_INFO_V1(ffiinews_uwildmat);

/* Wrapper for INN's function uwildmat.  Needs parameters in UTF-8. */
Datum ffiinews_uwildmat(PG_FUNCTION_ARGS) {
    VarChar *text = PG_GETARG_VARCHAR_P(0);
    VarChar *pattern = PG_GETARG_VARCHAR_P(1);
    int text_len = VARSIZE(text)-VARHDRSZ;
    int pattern_len = VARSIZE(pattern)-VARHDRSZ;
    char *tmp_text = (char *)malloc(text_len+1);
    if (tmp_text == NULL)
        ; /* What now? */
    char *tmp_pattern = (char *)malloc(pattern_len+1);
    if (tmp_pattern == NULL)
        ; /* What now? */
    strncpy(tmp_text, VARDATA(text), text_len);
    tmp_text[text_len] = '\0';
    strncpy(tmp_pattern, VARDATA(pattern), pattern_len);
    tmp_pattern[pattern_len] = '\0';
    bool matches = uwildmat(tmp_text, tmp_pattern);
    free(tmp_pattern);
    free(tmp_text);
    PG_RETURN_BOOL(matches);
}

-- 
Felix E. Klee

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