Environment variables in Postgres C extension
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I cannot get environment variable in my PostgreSQL C extension code.
For example, this function always returns
111
:#include "postgres.h" #include "fmgr.h" #include
PG_MODULE_MAGIC;
PG_FUNCTION_INFO_V1(myinc);
Datum
myinc(PG_FUNCTION_ARGS)
{
int32 arg = PG_GETARG_INT32(0);
char* envar = getenv("MYINC");
if (envar) {
PG_RETURN_INT32(arg + atoi(envar));
} else {
PG_RETURN_INT32(111);
}
}
While this C program works as expected, it prints whatever
MYINC
is:#include #include
int main()
{
printf("MYINC: %s", getenv("MYINC"));
return 0;
}
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That should work just fine. Note, however, that it will take the variable from the environment of the PostgreSQL server process, not your current client process.