18.2.71. PMIx_Value_get_size

PMIx_Value_get_size — Compute the size (in bytes) of the data payload in a pmix_value_t(5) structure.

18.2.71.1. SYNOPSIS

#include <pmix.h>

pmix_status_t PMIx_Value_get_size(const pmix_value_t *val,
                                  size_t *size);

18.2.71.2. INPUT PARAMETERS

val: Pointer to the pmix_value_t(5) whose payload size is to be computed.

18.2.71.3. OUTPUT PARAMETERS

size: Pointer to a size_t variable where the computed size, in bytes, will be returned.

18.2.71.4. DESCRIPTION

Compute and return the size, in bytes, of the data payload contained in a pmix_value_t(5) structure. The reported size is determined from the type field of the value and reflects the amount of storage occupied by the data itself.

For scalar data types (e.g., PMIX_INT32, PMIX_SIZE, PMIX_DOUBLE), the returned size is simply the size of that type. For types that carry variable-length or referenced data, the computation includes that data as well:

For a PMIX_STRING, the returned size includes the length of the string plus one byte for the terminating NULL.
For PMIx-defined structures and referenced objects (e.g., a pmix_data_buffer_t), the returned size includes both the size of the structure and the size of the data it references.

In all cases, the size of the pmix_value_t(5) structure itself is added to the returned value, so size reflects the total storage associated with the value, not just its payload.

The source pmix_value_t(5) is not altered by this function.

18.2.71.5. RETURN VALUE

Returns PMIX_SUCCESS on success. On error, a negative value corresponding to a PMIx error constant is returned, including:

PMIX_ERR_UNKNOWN_DATA_TYPE — the type field of the value is PMIX_UNDEF or otherwise not a recognized PMIx data type, so the size could not be computed.

Any other negative value indicates an appropriate error condition. PMIx error constants are defined in pmix_common.h.

18.2.71.6. NOTES

The returned size includes the size of the pmix_value_t(5) structure itself in addition to the size of its data payload. When the value references a PMIx-defined structure (such as a pmix_byte_object_t), the size accounts for the referenced structure and its contents.