I am trying to update/alter two columns-comment and id in a table called xxx using postgresql. Though the compiler does not show any errors but Valgrind gives major memory leak errors. The code is:
int main() { PGconn *conn; PGresult *res; int i=0,nFields=0,row=0,col=0; conn = PQconnectdb("dbname=test1 host=localhost user=postgres password=yyy"); if(PQstatus(conn) == CONNECTION_BAD) { fprintf(stderr, "Connection to database \"%s\" failed.\n", PQerrorMessage(conn)); fprintf(stderr, "%s", PQerrorMessage(conn)); exit_nicely(conn); } res = PQexec(conn, "IF COL_LENGTH('xxx','comment') IS NULL"); if(res) res = PQexec(conn, "ALTER TABLE xxx ADD comment VARCHAR(500)"); else res = PQexec(conn, "UPDATE TABLE xxx ADD comment VARCHAR(500)"); res = PQexec(conn, "IF COL_LENGTH('xxx','id') IS NULL"); if(res) res = PQexec(conn, "ALTER TABLE xxx ADD id VARCHAR(50)"); else res = PQexec(conn, "UPDATE TABLE xxx ADD id VARCHAR(50)"); res = PQexec(conn, "SELECT * FROM xxx"); if((!res) || (PQresultStatus(res) != PGRES_TUPLES_OK)) { fprintf(stderr, "SELECT command did not return tuples properly\n"); PQclear(res); } PQclear(res); PQfinish(conn); return 0; } Valgrind gives the following errors: $ valgrind --track-origins=yes --leak-check=full ./Gwidd_uniprot_map2 xaa ==4525== Memcheck, a memory error detector ==4525== Copyright (C) 2002-2010, and GNU GPL'd, by Julian Seward et al. ==4525== Using Valgrind-3.6.1 and LibVEX; rerun with -h for copyright info ==4525== Command: ./Gwidd_uniprot_map2 xaa ==4525== --4525-- ./Gwidd_uniprot_map2: --4525-- dSYM directory has wrong UUID; consider using --dsymutil=yes ==4525== ==4525== HEAP SUMMARY: ==4525== in use at exit: 262,994 bytes in 751 blocks ==4525== total heap usage: 1,012 allocs, 261 frees, 345,158 bytes allocated ==4525== ==4525== 2,248 (200 direct, 2,048 indirect) bytes in 1 blocks are definitely lost in loss record 400 of 414 ==4525== at 0x100011345: malloc (vg_replace_malloc.c:236) ==4525== by 0x10007B7E0: PQmakeEmptyPGresult (in /usr/lib/libpq.5.dylib) ==4525== by 0x10008DF30: pqGetErrorNotice3 (in /usr/lib/libpq.5.dylib) ==4525== by 0x10008CC00: pqParseInput3 (in /usr/lib/libpq.5.dylib) ==4525== by 0x10007ECD9: parseInput (in /usr/lib/libpq.5.dylib) ==4525== by 0x10007EE3F: PQgetResult (in /usr/lib/libpq.5.dylib) ==4525== by 0x10007F6F1: PQexecFinish (in /usr/lib/libpq.5.dylib) ==4525== by 0x10007F1DC: PQexec (in /usr/lib/libpq.5.dylib) ==4525== by 0x10000199A: main (in ./Gwidd_uniprot_map2) ==4525== ==4525== 2,248 (200 direct, 2,048 indirect) bytes in 1 blocks are definitely lost in loss record 401 of 414 ==4525== at 0x100011345: malloc (vg_replace_malloc.c:236) ==4525== by 0x10007B7E0: PQmakeEmptyPGresult (in /usr/lib/libpq.5.dylib) ==4525== by 0x10008DF30: pqGetErrorNotice3 (in /usr/lib/libpq.5.dylib) ==4525== by 0x10008CC00: pqParseInput3 (in /usr/lib/libpq.5.dylib) ==4525== by 0x10007ECD9: parseInput (in /usr/lib/libpq.5.dylib) ==4525== by 0x10007EE3F: PQgetResult (in /usr/lib/libpq.5.dylib) ==4525== by 0x10007F6F1: PQexecFinish (in /usr/lib/libpq.5.dylib) ==4525== by 0x10007F1DC: PQexec (in /usr/lib/libpq.5.dylib) ==4525== by 0x1000019B5: main (in ./Gwidd_uniprot_map2) ==4525== ==4525== 2,248 (200 direct, 2,048 indirect) bytes in 1 blocks are definitely lost in loss record 402 of 414 ==4525== at 0x100011345: malloc (vg_replace_malloc.c:236) ==4525== by 0x10007B7E0: PQmakeEmptyPGresult (in /usr/lib/libpq.5.dylib) ==4525== by 0x10008DF30: pqGetErrorNotice3 (in /usr/lib/libpq.5.dylib) ==4525== by 0x10008CC00: pqParseInput3 (in /usr/lib/libpq.5.dylib) ==4525== by 0x10007ECD9: parseInput (in /usr/lib/libpq.5.dylib) ==4525== by 0x10007EE3F: PQgetResult (in /usr/lib/libpq.5.dylib) ==4525== by 0x10007F6F1: PQexecFinish (in /usr/lib/libpq.5.dylib) ==4525== by 0x10007F1DC: PQexec (in /usr/lib/libpq.5.dylib) ==4525== by 0x1000019DF: main (in ./Gwidd_uniprot_map2) ==4525== ==4525== 2,248 (200 direct, 2,048 indirect) bytes in 1 blocks are definitely lost in loss record 403 of 414 ==4525== at 0x100011345: malloc (vg_replace_malloc.c:236) ==4525== by 0x10007B7E0: PQmakeEmptyPGresult (in /usr/lib/libpq.5.dylib) ==4525== by 0x10008DF30: pqGetErrorNotice3 (in /usr/lib/libpq.5.dylib) ==4525== by 0x10008CC00: pqParseInput3 (in /usr/lib/libpq.5.dylib) ==4525== by 0x10007ECD9: parseInput (in /usr/lib/libpq.5.dylib) ==4525== by 0x10007EE3F: PQgetResult (in /usr/lib/libpq.5.dylib) ==4525== by 0x10007F6F1: PQexecFinish (in /usr/lib/libpq.5.dylib) ==4525== by 0x10007F1DC: PQexec (in /usr/lib/libpq.5.dylib) ==4525== by 0x1000019FA: main (in ./Gwidd_uniprot_map2) ==4525== ==4525== LEAK SUMMARY: ==4525== definitely lost: 800 bytes in 4 blocks ==4525== indirectly lost: 8,192 bytes in 4 blocks ==4525== possibly lost: 0 bytes in 0 blocks ==4525== still reachable: 254,002 bytes in 743 blocks ==4525== suppressed: 0 bytes in 0 blocks ==4525== Reachable blocks (those to which a pointer was found) are not shown. ==4525== To see them, rerun with: --leak-check=full --show-reachable=yes ==4525== ==4525== For counts of detected and suppressed errors, rerun with: -v ==4525== ERROR SUMMARY: 4 errors from 4 contexts (suppressed: 0 from 0) Please provide suggestions to solve the problem. Thanks!