SDL_error_c.h File Reference

#include "./SDL_internal.h"

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Data Structures
struct	SDL_error

Macros
#define	ERR_MAX_STRLEN   128

Functions
SDL_error *	SDL_GetErrBuf (void)

Macro Definition Documentation

ERR_MAX_STRLEN

#define ERR_MAX_STRLEN   128

Definition at line 30 of file SDL_error_c.h.

Function Documentation

SDL_GetErrBuf()

SDL_error* SDL_GetErrBuf

(

void

)

Definition at line 205 of file SDL_thread.c.

{
#if SDL_THREADS_DISABLED
    /* Non-thread-safe global error variable */
    static SDL_error SDL_global_error;
    return &SDL_global_error;
#else
    static SDL_SpinLock tls_lock;
    static SDL_bool tls_being_created;
    static SDL_TLSID tls_errbuf;
    static SDL_error SDL_global_errbuf;
    const SDL_error *ALLOCATION_IN_PROGRESS = (SDL_error *)-1;
    SDL_error *errbuf;
 
    /* tls_being_created is there simply to prevent recursion if SDL_TLSCreate() fails.
       It also means it's possible for another thread to also use SDL_global_errbuf,
       but that's very unlikely and hopefully won't cause issues.
     */
    if (!tls_errbuf && !tls_being_created) {
        SDL_AtomicLock(&tls_lock);
        if (!tls_errbuf) {
            SDL_TLSID slot;
            tls_being_created = SDL_TRUE;
            slot = SDL_TLSCreate();
            tls_being_created = SDL_FALSE;
            SDL_MemoryBarrierRelease();
            tls_errbuf = slot;
        }
        SDL_AtomicUnlock(&tls_lock);
    }
    if (!tls_errbuf) {
        return &SDL_global_errbuf;
    }
 
    SDL_MemoryBarrierAcquire();
    errbuf = (SDL_error *)SDL_TLSGet(tls_errbuf);
    if (errbuf == ALLOCATION_IN_PROGRESS) {
        return &SDL_global_errbuf;
    }
    if (!errbuf) {
        /* Mark that we're in the middle of allocating our buffer */
        SDL_TLSSet(tls_errbuf, ALLOCATION_IN_PROGRESS, NULL);
        errbuf = (SDL_error *)SDL_malloc(sizeof(*errbuf));
        if (!errbuf) {
            SDL_TLSSet(tls_errbuf, NULL, NULL);
            return &SDL_global_errbuf;
        }
        SDL_zerop(errbuf);
        SDL_TLSSet(tls_errbuf, errbuf, SDL_free);
    }
    return errbuf;
#endif /* SDL_THREADS_DISABLED */
}

References NULL, SDL_AtomicLock, SDL_AtomicUnlock, SDL_FALSE, SDL_free, SDL_malloc, SDL_MemoryBarrierAcquire, SDL_MemoryBarrierRelease, SDL_TLSCreate(), SDL_TLSGet(), SDL_TLSSet(), SDL_TRUE, and SDL_zerop.

Referenced by SDL_ClearError(), SDL_GetError(), SDL_GetErrorMsg(), and SDL_SetError().