diff options
Diffstat (limited to 'src/interfaces/libpq/pqexpbuffer.h')
| -rw-r--r-- | src/interfaces/libpq/pqexpbuffer.h | 20 |
1 files changed, 18 insertions, 2 deletions
diff --git a/src/interfaces/libpq/pqexpbuffer.h b/src/interfaces/libpq/pqexpbuffer.h index b834ac48082..3acca24b569 100644 --- a/src/interfaces/libpq/pqexpbuffer.h +++ b/src/interfaces/libpq/pqexpbuffer.h @@ -18,7 +18,7 @@ * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * - * $PostgreSQL: pgsql/src/interfaces/libpq/pqexpbuffer.h,v 1.19 2008/01/01 19:46:00 momjian Exp $ + * $PostgreSQL: pgsql/src/interfaces/libpq/pqexpbuffer.h,v 1.20 2008/11/26 00:26:23 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -35,6 +35,10 @@ * string size (including the terminating '\0' char) that we can * currently store in 'data' without having to reallocate * more space. We must always have maxlen > len. + * + * An exception occurs if we failed to allocate enough memory for the string + * buffer. In that case data points to a statically allocated empty string, + * and len = maxlen = 0. *------------------------- */ typedef struct PQExpBufferData @@ -47,6 +51,15 @@ typedef struct PQExpBufferData typedef PQExpBufferData *PQExpBuffer; /*------------------------ + * Test for a broken (out of memory) PQExpBuffer. + * When a buffer is "broken", all operations except resetting or deleting it + * are no-ops. + *------------------------ + */ +#define PQExpBufferBroken(str) \ + (!(str) || (str)->maxlen == 0) + +/*------------------------ * Initial size of the data buffer in a PQExpBuffer. * NB: this must be large enough to hold error messages that might * be returned by PQrequestCancel(). @@ -103,6 +116,8 @@ extern void termPQExpBuffer(PQExpBuffer str); /*------------------------ * resetPQExpBuffer * Reset a PQExpBuffer to empty + * + * Note: if possible, a "broken" PQExpBuffer is returned to normal. */ extern void resetPQExpBuffer(PQExpBuffer str); @@ -111,7 +126,8 @@ extern void resetPQExpBuffer(PQExpBuffer str); * Make sure there is enough space for 'needed' more bytes in the buffer * ('needed' does not include the terminating null). * - * Returns 1 if OK, 0 if failed to enlarge buffer. + * Returns 1 if OK, 0 if failed to enlarge buffer. (In the latter case + * the buffer is left in "broken" state.) */ extern int enlargePQExpBuffer(PQExpBuffer str, size_t needed); |