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PMIX_VALUE_GET_SIZE(3) OpenPMIx PMIX_VALUE_GET_SIZE(3)

PMIx_Value_get_size — Compute the size (in bytes) of the data payload in a pmix_value_t(5) <#man5-pmix-value-t> structure.

SYNOPSIS

#include <pmix.h>
pmix_status_t PMIx_Value_get_size(const pmix_value_t *val,


                                  size_t *size);


INPUT PARAMETERS

•
val: Pointer to the pmix_value_t(5) <#man5-pmix-value-t> whose payload size is to be computed.

OUTPUT PARAMETERS

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

DESCRIPTION

Compute and return the size, in bytes, of the data payload contained in a pmix_value_t(5) <#man5-pmix-value-t> 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) <#man5-pmix-value-t> 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) <#man5-pmix-value-t> is not altered by this function.

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.

NOTES

The returned size includes the size of the pmix_value_t(5) <#man5-pmix-value-t> 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.

See also:

PMIx_Info_get_size(3) <#man3-pmix-info-get-size>, PMIx_Value_unload(3) <#man3-pmix-value-unload>, pmix_value_t(5) <#man5-pmix-value-t>, pmix_byte_object_t(5) <#man5-pmix-byte-object-t>, pmix_data_buffer_t(5) <#man5-pmix-data-buffer-t>


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September 27, 2026