Calling C Function That Uses getenv() Doesn't Work (46851)

SUMMARY

When a compiled Basic program CALLs a C function that uses the getenv() function, no path is returned from getenv(). The getenv() function in C uses the ENVIRON variable to access the environment table. The ENVIRON variable is an array of pointers to the strings that constitute the process environment. This variable is initialized by the C start-up code. Since the C function is CALLed from the Basic program, the C start-up code is not executed; therefore, the ENVIRON variable is not initialized (it is NUL by default).

To work around this problem, use the ENVIRON$ function in the Basic program and pass the desired path to the C function.

This information applies to Microsoft QuickBasic Versions 4.00, 4.00b, and 4.50; to Microsoft Basic Compiler Versions 6.00 and 6.00b; to Microsoft Basic PDS Version 7.00; to Microsoft QuickC Compiler Versions 1.00, 1.01, 2.00, 2.01; and to Microsoft C Compiler Versions 5.00 and 5.10.

' Basic Source Code:
DECLARE SUB EnvironTest CDECL ()
CLS
CALL EnvironTest
END
/* C source code: */ 
#include <stdlib.h>
#include <stdio.h>
void EnvironTest(void)
{
  char *temp;
  temp = getenv( "PATH" );
  printf( "Path: %s\nenviron: %x\n", temp, environ );
}