PR_MALLOC
syntax #include <prmem.h> void * pr_malloc(_bytes); parameter _bytes size of the requested memory block.

Memory Management Operations
memory allocation functions are: pr_malloc pr_calloc pr_realloc pr_free pr_malloc(), pr_calloc(), pr_realloc(), and pr_free() have the same signatures as their libc equivalents malloc(), calloc(), realloc(), and free(), and have the same semantics.
... (note that the argument type size_t is replaced by pruint32.) memory allocated by pr_malloc(), pr_calloc(), or pr_realloc() must be freed by pr_free().
... memory allocation macros macro versions of the memory allocation functions are available, as well as additional macros that provide programming convenience: pr_malloc pr_new pr_realloc pr_calloc pr_newzap pr_delete pr_freeif ...

Choosing the right memory allocator
pr_alloc() (do not use, no users and only exists in /security/; use pr_malloc() instead) pr_malloc() == pr_malloc pr_calloc() == pr_calloc pr_realloc() == pr_realloc pr_free() pr_new (pass in a struct to allocate its size) pr_newzap (same as pr_new, but zeros memory) pr_delete (pr_free() and also clears the pointer) pr_freeif special cases pr_smprintf(), pr_sprintf_append(), pr_vsmprintf() and pr_vsprintf_append() must be freed with pr_smpr...

nss tech note1
with sec_asn1decodeitem, it can be null, and if so, the decoder will allocate from the heap using pr_malloc .

NSS PKCS11 Functions
this memory must have been allocated with pr_malloc or pl_strdup.

pkfnc.html
this memory must have been allocated with pr_malloc or pl_strdup.

sslintro.html
functions that can be used by both clients and servers during communication include the following: pr_send or pr_write pr_read or pr_recv pr_geterror pr_getpeername pr_sleep pr_malloc pr_free pr_poll pr_now pr_intervaltomilliseconds pr_millisecondstointerval pr_shutdown pr_close ssl_invalidatesession after establishing a connection, an application first calls pr_send, pr_recv, pr_read, pr_write, or ssl_forcehandshake to initiate the handshake.