====== command g ======

**Format:** ‘g’

**Meaning:** Read general registers.

**Reply:** ‘XX…’

Each byte of register data is described by two hex digits. The bytes with the register are transmitted in **target byte order**. The size of each register and their position within the ‘g’ packet are determined by the target description (see Target Descriptions); in the absence of a target description, this is done using code internal to GDB; typically this is some customary register layout for the architecture in question.

When reading registers, the stub may also return a string of literal ‘x’’s in place of the register data digits, to indicate that the corresponding register’s value is unavailable. For example, when reading registers from a trace frame (see Using the Collected Data), this means that the register has not been collected in the trace frame. When reading registers from a live program, this indicates that the stub has no means to access the register contents, even though the corresponding register is known to exist. Note that if a register truly does not exist on the target, then it is better to not include it in the target description in the first place. 

**Example:** for an architecture with 4 registers of 4 bytes each, the following reply indicates to GDB that registers 0 and 2 are unavailable, while registers 1 and 3 are available, and both have zero value: 
gdb to gdb-server: <code>$g#00</code>
gdb-server to gdb: <code>xxxxxxxx00000000xxxxxxxx00000000</code>