diff options
Diffstat (limited to 'src/backend/utils/misc/README')
| -rw-r--r-- | src/backend/utils/misc/README | 15 |
1 files changed, 7 insertions, 8 deletions
diff --git a/src/backend/utils/misc/README b/src/backend/utils/misc/README index 6e294386f7..85d97d29b6 100644 --- a/src/backend/utils/misc/README +++ b/src/backend/utils/misc/README @@ -51,13 +51,13 @@ out-of-memory. This might be used for example to canonicalize the spelling of a string value, round off a buffer size to the nearest supported value, or replace a special value such as "-1" with a computed default value. If the -function wishes to replace a string value, it must malloc (not palloc) -the replacement value, and be sure to free() the previous value. +function wishes to replace a string value, it must guc_malloc (not palloc) +the replacement value, and be sure to guc_free() the previous value. * Derived information, such as the role OID represented by a user name, -can be stored for use by the assign hook. To do this, malloc (not palloc) +can be stored for use by the assign hook. To do this, guc_malloc (not palloc) storage space for the information, and return its address at *extra. -guc.c will automatically free() this space when the associated GUC setting +guc.c will automatically guc_free() this space when the associated GUC setting is no longer of interest. *extra is initialized to NULL before call, so it can be ignored if not needed. @@ -255,10 +255,9 @@ maintained by GUC. GUC Memory Handling ------------------- -String variable values are allocated with malloc/strdup, not with the -palloc/pstrdup mechanisms. We would need to keep them in a permanent -context anyway, and malloc gives us more control over handling -out-of-memory failures. +String variable values are allocated with guc_malloc or guc_strdup, +which ensure that the values are kept in a long-lived context, and provide +more control over handling out-of-memory failures than bare palloc. We allow a string variable's actual value, reset_val, boot_val, and stacked values to point at the same storage. This makes it slightly harder to free |