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Reference/es_mbc_addfldstr
Syntax
int es_mbc_addfldstr( struct es_mbc *cls, const char *fieldnm, unsigned fldsize );
Arguments
struct es_mbc *cls |
A database class. |
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const char *fieldnm |
Field name. |
unsigend fldsize |
Width of field in bytes, not to exceed 128. |
Return Codes
ES_ERROR_NONE |
Success. No errors. | |
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ES_ERROR_UNKNOWNFIELD |
Field name does not exist in class definition. | |
ES_ERROR_INVALIDFIELDTYPE |
Field is not of type ES_FLDTYPE_STR. |
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ES_ERROR_INVALIDFIELDSIZE |
Field exceeds 128 bytes in size. |
Description
es_mbc_addfldstr defines the size of a fixed-width user-defined field. Field sizes cannot exceed 128 bytes in size. Field sizes default to the word-size of the machine. The API may choose to increase the field size a little for reasons of efficiency of fetch and update (in a similar way that a compiler might choose to change the size of a declared struct in C).
Fixed-width user-defined fields are an efficiency saving in cases where a collection of values are likely always to be fetched or updated together.