 The GNU C Library Reference Manual

Official manual: sourceware.org/glibc/manual/2.24/html_node/Basic-Allocation.html . Version 2.24, section 3.2.2.1, Basic Memory Allocation: malloc returns a pointer to a block of the requested byte count or a null pointer; allocated contents require initialization. This pinned section was directly verified; it is not a claim that 2.24 is the current library release.