win32dlopen.c

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/*-------------------------------------------------------------------------
 *
 * win32dlopen.c
 *    dynamic loader for Windows
 *
 * Portions Copyright (c) 1996-2024, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 *
 * IDENTIFICATION
 *    src/port/win32dlopen.c
 *
 *-------------------------------------------------------------------------
 */
 
#include "c.h"
 
static char last_dyn_error[512];
 
static void
set_dl_error(void)
{
    DWORD       err = GetLastError();
 
    if (FormatMessage(FORMAT_MESSAGE_IGNORE_INSERTS |
                      FORMAT_MESSAGE_FROM_SYSTEM,
                      NULL,
                      err,
                      MAKELANGID(LANG_ENGLISH, SUBLANG_DEFAULT),
                      last_dyn_error,
                      sizeof(last_dyn_error) - 1,
                      NULL) == 0)
    {
        snprintf(last_dyn_error, sizeof(last_dyn_error) - 1,
                 "unknown error %lu", err);
    }
}
 
char *
dlerror(void)
{
    if (last_dyn_error[0])
        return last_dyn_error;
    else
        return NULL;
}
 
int
dlclose(void *handle)
{
    if (!FreeLibrary((HMODULE) handle))
    {
        set_dl_error();
        return 1;
    }
    last_dyn_error[0] = 0;
    return 0;
}
 
void *
dlsym(void *handle, const char *symbol)
{
    void       *ptr;
 
    ptr = GetProcAddress((HMODULE) handle, symbol);
    if (!ptr)
    {
        set_dl_error();
        return NULL;
    }
    last_dyn_error[0] = 0;
    return ptr;
}
 
void *
dlopen(const char *file, int mode)
{
    HMODULE     h;
    int         prevmode;
 
    /* Disable popup error messages when loading DLLs */
    prevmode = SetErrorMode(SEM_FAILCRITICALERRORS | SEM_NOOPENFILEERRORBOX);
    h = LoadLibrary(file);
    SetErrorMode(prevmode);
 
    if (!h)
    {
        set_dl_error();
        return NULL;
    }
    last_dyn_error[0] = 0;
    return (void *) h;
}