[#base_blob-09-2constructor-00]
= xref:base_blob-09.adoc[base_blob]::base_blob
:relfileprefix: ../
:mrdocs:

Constructors

== Synopses

Declared in `<uint256.h>`

Constructs a zero‐valued blob.


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
constexpr
xref:base_blob-09/2constructor-03.adoc[base_blob]();
----

[.small]#xref:base_blob-09/2constructor-03.adoc[_» more..._]#

Constructs a blob at compile time from a hex string.


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
consteval
explicit
xref:base_blob-09/2constructor-0e.adoc[base_blob](std::string_view hex_str);
----

[.small]#xref:base_blob-09/2constructor-0e.adoc[_» more..._]#

Constructs a blob from a single byte constant between 1 and 255.


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
constexpr
explicit
xref:base_blob-09/2constructor-02.adoc[base_blob](uint8_t v);
----

[.small]#xref:base_blob-09/2constructor-02.adoc[_» more..._]#

Constructs a blob by copying bytes from a span.


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
constexpr
explicit
xref:base_blob-09/2constructor-09.adoc[base_blob](std::span<unsigned char const> vch);
----

[.small]#xref:base_blob-09/2constructor-09.adoc[_» more..._]#

== Parameters

[cols="1,4"]
|===
| Name| Description
| *hex_str*
| A hex string that must fit the blob exactly.
| *v*
| The byte value placed in the first position of the blob.
| *vch*
| A span of exactly WIDTH bytes to copy into the blob.
|===


[.small]#Created with https://www.mrdocs.com[MrDocs]#